Assuming you have barrows gloves, 46 def isn't a biggy. I got 46 def right before 90 attack, I was pissed yea but its not terrible(Was almost 90 att on a slayer task using d hally, figured I would finish lvl off but apparently hally on accurate gives defense xp)
My zerker ended up ebing 94-99-46 94hp 94 mage 90 range 52 prayer before it was banned for autoing.
I would recommend staying 50 prayer, that way you will still be 106 maxed instead of 107.(Maybe, check on a calculator if you will be 107 with 50 prayer might aswell get 52).
*Note* Just saw your thieving so you haven't done DT which means you haven't done RFD, what gloves are you on?
Also, you are a long way from lunar, that's rough.